1. Field of the Invention
The present invention relates to the field of an image scanning system, and more particularly, to a film scanner equipped with a cold cathode fluorescent lamp (CCFL) that can produce visible light and uniformize infrared light generated by an infrared source.
2. Description of the Prior Art
In a typical image scanner, light from an image is focused onto linear arrays of photo-sensors for scanning one line at a time. A two dimensional image is scanned by providing relative movement between the linear sensor arrays and the original image. In general, a color scanner measures the intensity of at least three relatively narrow bands of wavelengths of visible light, for example, bands of red, green and blue. A color scanner may sequentially present multiple bands of wavelengths to a single row of sensor elements by sequentially activating different colored light sources.
A typical film scanner developed by Nikon uses three color LEDs to illuminate the film. The LEDs have well-controlled light characteristics, and are not subject to the fading of conventional color filter materials. The LED light source is also somewhat collimated (the light waves travel in relatively straight lines), which produces very sharp scans, but also has a tendency to emphasize scratches, dust, and film defects.
Please refer to FIG. 1. FIG. 1 is a schematic diagram of a prior film scanner 10 equipped with LED light sources. A film scanner 10 is used to scan a film or negative 11. The film scanner 10 comprises four LEDs 12a, 12b, 12c and 12d, a ground glass 14, a diffuser 16, a projection lens 18, and a detector or light sensor 20. The LEDs 12a, 12b, or 12c can produce red light, green light, or blue light respectively, and the LED 12d produces infrared light. The ground glass 14 and the diffuser 16 are used to generate uniform and parallel scanning light. When scanning, the film scanner 10 performs scans by visible light that is generated by the LEDs 12a, 12b, and 12c. Then, the film scanner 10 performs scans by infrared light emitted from the LED 12d. Since the infrared light cannot pass through particles of dust or scratches on the film 11, the images of the film 11 can be restored.
When scanning the film 11 by the prior art film scanner 10 as described above, the ground glass 14 and diffuser 16 are both essential since uniform and parallel infrared light is required. This leads to a more complicated assembly and therefore a more costly design of the film scanner 10.
It is therefore a primary objective of the claimed invention to provide a new film scanner design that utilizes a cold cathode fluorescent lamp (CCFL) for providing visible light and uniformizing infrared light.
It is another objective of the claimed invention to provide a more cost-effective film scanner by replacing the ground glass and the diffuser of a prior art film scanner with a cold cathode lamp.
In accordance with the objectives of the claimed invention, the claimed invention provides a film scanner comprising a cold cathode fluorescent lamp for producing visible light to scan a film containing a plurality of photographic images therein, an infrared source for producing infrared light to scan the film, and a detector for sensing the visible light and the infrared light transmitting the film to produce corresponding image signals. The cold cathode fluorescent lamp is disposed between the infrared source and the film and the cold cathode fluorescent lamp is in contact with the infrared source. In this way, before arriving at the film the infrared light is substantially uniformized by passing through the cold cathode fluorescent lamp.
It is an advantage of the claimed invention that the film scanner is not complicated. Further, the film scanner according to the claimed invention saves a lot of space.
It is another advantage of the claimed invention that the film scanner according to the claimed invention is very cost-effective since both a ground glass and a diffuser are eliminated.
These and other objectives and advantages of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings.